Application Of 3D Printing Research Articles

3D printing of cementitious composites with seashell particles: Mechanical and microstructural analysis

Seashells are abundantly available as waste products from the seafood industry and from coastal areas. Accordingly, processed shells can be used to partially replace aggregates in traditional concrete. This paper investigates the effects of different proportions of seashell particles on the mechanical and microstructural properties of 3D-printed cementitious composites. The seashells were crushed and milled to be transformed into seashell particles, replacing the river sand at 15 wt% and 30 wt%. It was found that when the seashell particle content increased to 15 wt% and 30 wt%, the mechanical strengths all decreased significantly, which could be attributed to the increasing volumetric proportion of voids and the lower elastic modulus of seashell particles compared to river sand. However, when the seashell particle proportion further rose from 15 wt% to 30 wt%, the mechanical strengths did not continue decreasing substantially. Instead, the compressive and indirect tensile strengths nearly levelled off with minor fluctuations. Based on the microstructural analysis results, it was inferred that the fine seashell powders as part of the seashell particles, which were comprised of aragonite-based calcium carbonate, participated in the cement hydration process that could help with microstructure densification of the cement matrix. This positive effect brought by the fine seashell powders was thought to prevent the further weakening of mechanical properties. Overall, this study aims to understand the role of seashell particles on the mechanical performance of 3D-printed cementitious composites from the perspectives of microstructural characteristics, further promoting the utilisation of waste seashells in 3D concrete printing applications.

Microcrystalline Cellulose from Aloe Plant Waste as a Platform for Green Materials: Preparation, Chemical Functionalization, and Application in 3D Printing

Microcrystalline Cellulose from Aloe Plant Waste as a Platform for Green Materials: Preparation, Chemical Functionalization, and Application in 3D Printing

3D-printed multi-functional foamed concrete building components: Material properties, component design, and 3D printing application

The use of multi-density foamed concretes (FCs) to produce multi-functional building components by 3D Concrete Printing (3DCP) is investigated. The use of medium-density 3D-printed foamed concrete (3DPFC_800), primarily serving a load-bearing role, and ultra-lightweight foamed concrete (ULFC_300), as thermal insulation material poured in the voids defined by the former, is proposed. This enables meeting diverse performance requirements within a single cementitious matrix, eliminating the need for multiple materials. The main properties of the proposed mixes are investigated. The compressive strength and thermal conductivity are equal to 7.04 MPa and 0.205 W/mK, and 1.43 MPa and 0.072 W/mK for 3DPFC_800 and ULFC_300, respectively. A successful 2D-printing test validates the suitability of 3DPFC_800 for 3DCP, and a robotic arm is employed for 3DCP tests. The proposed application allows for further knowledge on the use of FC in 3DCP and the identification of some issues and challenges that still need to be addressed.

The Mechanical and Physical Properties of 3D Printing Filament made from Recycled Polypropylene and Ground Tyre Rubber Treated with Alkali

When molten, used vehicle tyres are unable to decompose or be recycled. Despite global efforts to find new uses for these materials, many worn tyres are still dumped in landfills. Therefore, this study proposes using ground tyre rubber (GTR) as a fill material for recycled polypropylene 3D printing filament. The filament composite’s physical and mechanical properties will be assessed in this investigation. GTR is expected to give the filament elastic characteristics, which could lead to rubber-like filaments. This study filled recycled polypropylene (rPP) polymer matrix composites with GTR to make filament. The mechanical and physical properties of a 3D-printed specimen made from rPP and GTR filament with varying compositions were analysed. Compared to pure rPP, rPP/GTR samples with 3 wt% GTR had a maximum tensile strength of 716.76 MPa. The flexural test findings showed that rPP/GTR with 3 wt% GTR had the highest flexural strength at 80.53 MPa, followed by rPP/1 wt% GTR at 65.38 MPa. In physical tests, the rPP/GTR at 5 wt% GTR had the highest water absorption at 5.41 %, and the wt% of GTR connected directly with water absorption. This study has shown that affordable, environmentally friendly rPP/GTR filaments can be developed with less amount of GTR content (3 wt%) and used for 3D printing applications, helping to lessen the impact of plastic and waste while having valuable mechanical and physical properties that are comparable to those of the pure polypropylene material produced.

Effect of κ-carrageenan on physicochemical and 3D printing properties of walnut protein-stabilized emulsion gel

Walnut protein (WP)-stabilized oil-in-water (O/W) emulsion gel can be used to produce food through 3D printing, but there was a problem of poor printing accuracy. We added κ-carrageenan (KG) to enhance the shape retention of corresponding printed products. In this study, the effect of KG on various physicochemical properties of the WP-stabilized O/W emulsion gel was investigated. The rheology results showed that adding KG significantly enhanced the mechanical strength and the viscosity of the produced WP-KG emulsion gel. The Lissajous curves indicated that the response of all samples under 10% low strain was mainly elastic, and the gels with 0.2, 0.3 and 0.4 (w/w) KG had great shear recovery performance against deformation. The increased KG content in the gel reduced the number of pores, promoted emulsions droplet aggregation, reduced crystallinity, and decreased the water-binding ability of the gel. Adding KG to the gel significantly increased its hardness, resilience, and gumminess while reducing its springiness. Various emulsion gels with different KG contents were further used as the bioink for 3D printing. The result suggested that KG improved the printing accuracy and self-supporting ability of 3D-printed products. However, excessive KG (>0.4%, w/w) caused uneven extruded filaments, reduced the adherence between printed layers and decreased printing accuracy. Among various WP-KG emulsion gels, WP-KG0.3 was most appropriate for the 3D printing application.

Reproducibility and air gap pockets of 3D-printed brachytherapy applicator placement in high-dose-rate skin cancer

Background and PurposeThis study aimed to investigate the reproducibility of a novel approach using 3D printed brachytherapy applicators for the treatment of skin cancer. Specifically, we aimed to assess the accuracy of applicator placement and to minimize the existence of air gap pockets between the applicator and the patient’s skin. Materials and MethodsA total of 20 patients plans diagnosed with skin cancer were enrolled in this study. All patients underwent high dose rate (HDR) brachytherapy. To ensure precise applicator placement, patient-specific 3D printed applicators were designed based on individual body and tumor topography, utilizing data obtained from computer tomography (CT) scans. All applicators were fabricated using fused deposition modeling technology. ResultsThe error in applicator placement was measured and found to be less than 1.0 mm on average, with a standard deviation of 0.9 mm. Additionally, the average error in air gap pockets between the applicator and the patient’s skin was 0.4 mm (standard deviation was 0.5 mm). The study demonstrated that the personalized approach of 3D printed brachytherapy applicator placement in skin cancer treatment yielded highly accurate results. The average error of less than 1.0 mm in applicator positioning and the minimal air gap pockets demonstrated the reproducibility and precision of this technique. ConclusionOur study establishes the reproducibility and accuracy of 3D-printed brachytherapy applicator placement in the treatment of skin cancer. This personalized treatment approach offers a highly precise method for delivering radiation therapy, minimizing the risk to adjacent healthy tissues, and enhancing overall patient outcomes.

Non-Isocyanate Urethane Acrylate Derived from Isophorone Diamine: Synthesis, Characterization and Its Application in 3D Printing.

In this paper, urethane-based acrylates (UA) were prepared via an environmentally friendly non-isocyanate route. Isophorone diamine (IPDA) reacted with ethylene carbonate (EC), producing carbamate containing amine and hydroxyl groups, which further reacted with neopentyl glycol diacrylate (NPGDA) by aza Michael addition, forming UA. The structures of the obtained intermediates and UA were characterized by 1H NMR and electrospray ionization high-resolution mass spectrometry (ESI-HRMS). The photopolymerization kinetics of UA were investigated by infrared spectroscopy. The composite with obtained UA can be UV cured quickly to form a transparent film with a tensile strength of 21 MPa and elongation at break of 16%. After UV curing, the mono-functional urethane acrylate was copolymerized into the cross-linked network in the form of side chains. The hydroxyl and carbamate bonds on the side chains have high mobility, which make them easy to form stronger dynamic hydrogen bonds during the tensile process, giving the material a higher tensile strength and elongation at break. Therefore, the hydrogen bonding model of a cross-linked network is proposed. The composite with UA can be 3D printed into models.

Three-Dimensional Printing in Breast Reconstruction: Current and Promising Applications.

Three-dimensional (3D) printing is dramatically improving breast reconstruction by offering customized and precise interventions at various stages of the surgical process. In preoperative planning, 3D imaging techniques, such as computer-aided design, allow the creation of detailed breast models for surgical simulation, optimizing surgical outcomes and reducing complications. During surgery, 3D printing makes it possible to customize implants and precisely shape autologous tissue flaps with customized molds and scaffolds. This not only improves the aesthetic appearance, but also conforms to the patient's natural anatomy. In addition, 3D printed scaffolds facilitate tissue engineering, potentially favoring the development and integration of autologous adipose tissue, thus avoiding implant-related complications. Postoperatively, 3D imaging allows an accurate assessment of breast volume and symmetry, which is crucial in assessing the success of reconstruction. The technology is also a key educational tool, enhancing surgeon training through realistic anatomical models and surgical simulations. As the field evolves, the integration of 3D printing with emerging technologies such as biodegradable materials and advanced imaging promises to further refine breast reconstruction techniques and outcomes. This study aims to explore the various applications of 3D printing in breast reconstruction, addressing current challenges and future opportunities.

Advances in 3D printing for polymer composites: A review

AbstractThe potential of three‐dimensional (3D) printing technology in the fabrication of advanced polymer composites is becoming increasingly evident. This review discusses the latest research developments and applications of 3D printing in polymer composites. First, it focuses on the optimization of 3D printing technology, that is, by upgrading the equipment or components or adjusting the printing parameters, to make them more adaptable to the processing characteristics of polymer composites and to improve the comprehensive performance of the products. Second, it focuses on the 3D printable novel consumables for polymer composites, which mainly include the new printing filaments, printing inks, photosensitive resins, and printing powders, introducing the unique properties of the new consumables and different ways to apply them to 3D printing. Finally, the applications of 3D printing technology in the preparation of functional polymer composites (such as thermal conductivity, electromagnetic interference shielding, biomedicine, self‐healing, and environmental responsiveness) are explored, with a focus on the distribution of the functional fillers and the influence of the topological shapes on the properties and functional characteristics of the 3D printed products. The aim of this review is to deepen the understanding of the convergence between 3D printing technology and polymer composites and to anticipate future trends and applications.image

Applications and Advancement of 3D Printing in Pharmaceutical Manufacturing and Drug Delivery

Three-dimensional (3D) printing is an innovative additive manufacturing technology that has tremendous potential to revolutionize various aspects of the pharmaceutical industry including drug development, product design, manufacturing and delivery. 3D printing enables precise fabrication of complex drug products with customized compositions and geometries that cannot be produced through conventional processes. It facilitates rapid prototyping thereby accelerating drug development process. 3D printed dosage forms with capability of controlled, delayed and triggered drug release have potential to enhance patient compliance and therapeutic outcomes. Further, 3D printed personalized medications tailored to individual patient needs hold promise to improve medication accessibility and efficacy. Though 3D printing in pharmaceuticals is still in its infancy, ongoing research efforts aim to address key challenges including regulatory compliance, process optimization, material characterization and scale-up. As the technology advances further, 3D printing is expected to significantly transform pharmaceutical manufacturing by making on-demand, decentralized production a reality

Current trends and outlook of 3D printing in vascular surgery

BackgroundThree-dimensional (3D) printing is an additive manufacturing technique capable of the rapid prototyping of objects not feasible by other manufacturing methods. Vascular surgery has welcomed this technology and found it useful in many areas. MethodsThe integration of 3D-printed models in surgical training offers to bridge existing training gaps and increase exposure to complex pathology, while maintaining patient safety, during this time where the surgical education paradigm is shifting. Sterilizable 3D-printed models are being used to aid in the development of physician-modified endografts with excellent results. Rehearsing with patient-specific anatomic models before surgery has demonstrated evidence in improving operator confidence and decreased operative and fluoroscopy times. Research trends have demonstrated that technology such as printed custom implantable devices with tunable chemical and physical properties may be on the horizon. ResultsDespite all of this, the current use of 3D printing in vascular surgery is limited by factors such as materials, time constraints, and initial technical challenges to developing a printing protocol. All of these are areas actively being researched to improve applicability and adaptation of 3D printing. As its use continues to grow, 3D printing may find utility in meeting the global need for safe, timely, and affordable vascular surgical care. ConclusionsThe analysis delves into current uses, challenges, and future visions for this technology, emphasizing its transformative influence in the field of vascular surgery.

Decoding the nuances of scholarly output and publication metrics in orthodontics

This comprehensive manuscript endeavors to furnish orthodontic researchers with the necessary tools and knowledge to adeptly navigate the multifaceted landscape of academic publishing, thereby enhancing the efficacy and reach of their scholarly endeavors. It meticulously imparts critical insights and methodologies for comprehending and leveraging publication metrics, such as citation counts, the h-index, and Journal Impact Factors, to strategically plan research trajectories. Furthermore, it offers guidance on adeptly engaging with evaluation agencies such as the American Dental Association (ADA) and the National Institute of Dental and Craniofacial Research (NIDCR), thereby optimizing alignment with grant opportunities. Through the adept utilization of orthodontic bibliometrics, researchers can gain invaluable insights into prevailing collaboration trends and emerging research domains, thus facilitating informed decision-making and prioritization of scholarly pursuits. Additionally, the manuscript delves into the nuanced optimization of publication guidelines to maximize research impact. Spanning both established domains such as biomechanics, anchorage control, and aligner therapy, as well as burgeoning frontiers including 3D printing and artificial intelligence applications in aligner treatment, this manuscript equips orthodontic researchers with the requisite acumen to embark upon a journey of impactful scholarly contributions, thereby catalyzing advancements in patient care within the discipline.

Application of 3D Printing Positioning Technology in Parasagittal Meningioma Surgery: A Single-center Retrospective Study

To assess the utility of 3D printing positioning technology for resection of parasagittal meningioma. Information related to clinical history, application of 3D printing positioning technology, neuroimaging, surgical-related information, and postoperative hospital days of consecutive patients with parasagittal meningioma treated between January 2020 and December 2022 were retrospectively collected. Patients were divided into 2 groups based on whether the 3D printing positioning technology was applied. The values between groups were statistically compared. A total of 41 patients were enrolled. In cases using 3D printing positioning technology (14 patients), the location of craniotomy was much better and the postoperative hospital stay was much shorter. The application of 3D printing positioning technology in parasagittal meningioma surgery could improve the location of craniotomy, and reduce the postoperative hospital stay. It is a low-cost positioning technology, and has the potential to be applied to other superficial intracranial tumors.

Ready-to-print alginate inks: The effect of different divalent cations on physico-chemical properties of 3D printable alginate hydrogels

Studies about the use of different divalent cations to produce 3D printed scaffolds are almost limited to their application as secondary crosslinking agents after the printing of alginate. For this reason, this research aims to demonstrate the possibility to develop alginate hydrogel-inks for 3D-printing application, exploiting the ionotropic gelation in a preprint step, by paying attention to the role of divalent cations on hydrogel-inks properties. The investigation of transversal relaxation time highlighted differences among inks (barium-ink 90.04 ms, calcium-ink 84.33 ms, and zinc-ink 75.05 ms) suggesting a potential influence of different cations. If all the inks showed a shear thinning behaviour with similar flowability index (0.153±0.018), they were characterised by different consistency index (from 2420 to 574 Pa•s), extrudability and homogeneity, parameters that influence the printing setup. In fact, to reach the same flowability and thus low deviation in the layer width for all inks, a variation in printing pressure and speed was necessary. Overall, it can be deduced that alginate inks preparation following a preprint crosslinking approach could be a valid method to overcome the alginate printability issues underlining the possibility to select the crosslinking cation according to the technological properties wanted for the final matrix.

3D Printing with Bamboo: An Early-Stage Exploration towards Its Use in the Built Environment

Along with the circular bioeconomy principles, alternative ways of utilizing biomass waste streams are considered viable approaches to reaching sustainability goals. Accordingly, a growing body of literature is exploring new materials utilizing biomass in 3D-printing applications. This article presents early-stage research that initially investigates the usability of bamboo fibers and dust with bio-based binders in 3D printing towards its use in the design and production of the built environments. The research delves into solutions through a material tinkering approach to develop a bio-based composite material that can be used in fused deposition modeling (FDM). It includes mechanical strength analyses of printed specimens to understand the effects of different infill designs on the structural performance of objects printed using bamboo-based composite. Then, it demonstrates a design-to-production workflow that integrates a mechanically informed infill pattern within a self-supporting wall design that can be produced by 3D printing with bamboo. The workflow is presented with a partial demonstrator produced through robotic 3D printing. The article concludes with discussions and recommendations for further research.

4D Printing for Biomedical Applications.

4D (bio-)printing endows 3D printed (bio-)materials with multiple functionalities and dynamic properties. 4D printed materials have been recently used in biomedical engineering for the design and fabrication of biomedical devices, such as stents, occluders, microneedles, smart 3D-cell engineered microenvironments, drug delivery systems, wound closures, and implantable medical devices. However, the success of 4D printing relies on the rational design of 4D printed objects, the selection of smart materials, and the availability of appropriate types of external (multi-)stimuli. Here, this work first highlights the different types of smart materials, external stimuli, and design strategies used in 4D (bio-)printing. Then, it presents a critical review of the biomedical applications of 4D printing and discusses the future directions of biomedical research in this exciting area, including in vivo tissue regeneration studies, the implementation of multiple materials with reversible shape memory behaviors, the creation of fast shape-transformation responses, the ability to operate at the microscale, untethered activation and control, and the application of (machine learning-based) modeling approaches to predict the structure-property and design-shape transformation relationships of 4D (bio)printed constructs.

Nano-fly ash and clay for 3D-Printing concrete buildings: A fundamental study of rheological, mechanical and microstructural properties

Three-dimensional printing concrete (3DPC) represents a recent innovation in the construction and building research sector and novel approach to building techniques. The focus of this study is to develop an environmentally sustainable cementitious composite optimized for 3D printing applications. The research involved preparing 3D printing mixtures that comprised of 50 % Portland Cement (PC), 50 % Colorobia Clay (CC), and varying contents (0 % 5 %, 10 %, and 15 % by weight of cement) of Nano-Fly Ash (N-FA) under standardized printing parameters. The fresh mixture's properties have been evaluated and the mechanical and microstructural properties of the printed samples were assessed, subsequently. The findings demonstrated that incorporating N-FA into the cementitious mixes enhanced their flowability and workability. Specifically, the mix containing a low N-FA concentration of 5 wt% exhibited superior compressive strength relative to the other formulations. Additionally, flexural strength assessments indicated a minimum increase of 39.4 % across all mixes compared to the control 3D-printed mixture. Microstructural investigations by SEM imaging validated the anticipated formation of hydration products, namely calcium-silicate-hydrate (CSH) and ettringite, facilitated by the synergy between clay and fly ash. The t-statistical analysis further corroborated that the inclusion of N-FA significantly bolstered the strength attributes of the mixes designated for 3D printing. In conclusion, this study underscored the efficacy of integrating clay as a sustainable construction material within 3D printing applications. The utilization of clay-cement mixes, augmented with N-FA, emerged as a viable strategy to enhance the sustainability and reduce the carbon footprint of construction practices.

"Dissolve-on-Demand" 3D Printed Materials: Polymerizable Eutectics for Generating High Modulus, Thermoresponsive and Photoswitchable Eutectogels.

Solvent-free photopolymerization of vinyl monomers to produce high modulus materials with applications in 3D printing and photoswitchable materials is demonstrated. Polymerizable eutectic (PE) mixtures are prepared by simply heating and stirring various molar ratios of N-isopropylacrylamide (NIPAM), acrylamide (AAm) and 2-hydroxyethyl methacrylate (HEMA). The structural and thermal properties of the resulting mixtures are evaluated by 1D and 2D NMR spectroscopy as well as differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). UV photocuring kinetics of the PE mixtures is evaluated via in situ photo-DSC and photorheology measurements. The PE mixtures cure rapidly and display storage moduli that are orders of magnitude greater than equivalent copolymers cured in an aqueous medium. The versatility of these PE systems is demonstrated through the addition of a photoswitchable spiropyran acrylate monomer, as well as applying the PE formulation as a stereolithography (SLA)-based 3D printing resin. Due to the hydrogen-bonding network in PE systems, 3D printing of the eutectic resin is possible in the absence of crosslinkers. The addition of a RAFT agent to reduce average polymer chain length enables 3D printing of materials which retain their shape and can be dissolved on demand in appropriate solvents.

A blue light 3D printable hydrogel with water absorption, antibacterial, and hemostatic properties for skin wound healing

3D printing hydrogels are widely used in biomedicine because of their unique flexibility, water richness, biocompatibility, and most importantly, the ability to manufacture customized complex structures. Among the various 3D printing technologies for hydrogels, Digital Light Processing (DLP) is advantageous due to its fast speed and high precision. However, the high-energy ultraviolet (UV) light used in most DLP can damage the bio-materials, which limits their application in biomedicine. Herein, by introduction of multiple strengthening mechanisms (nanofibers, hydrogen bonds and coordination bonds) and double photo-initiators, we designed a 2-acrylamide-2-methyl-propanesulfonic acid (AMPS)-based hydrogel, which can be manufactured into various high-precision structures through 3D printing with blue light (450 nm). The printed hydrogel has good mechanical properties, high water absorption capacity, and strong water retention property. Vitro and in vivo experiments revealed that the printed hydrogels show excellent biocompatibility, hemostasis effect and antibacterial properties. We further expand the application of 3D printing in the field of precision medicine. The use of 3D printed hydrogels can achieve accurate fitting and wound repair according to the structure of the patient’s wound, providing better curative effect to the patient.

Nylons with Applications in Energy Generators, 3D Printing and Biomedicine.

Linear polyamides, known as nylons, are a class of synthetic polymers with a wide range of applications due to their outstanding properties, such as chemical and thermal resistance or mechanical strength. These polymers have been used in various fields: from common and domestic applications, such as socks and fishing nets, to industrial gears or water purification membranes. By their durability, flexibility and wear resistance, nylons are now being used in addictive manufacturing technology as a good material choice to produce sophisticated devices with precise and complex geometric shapes. Furthermore, the emergence of triboelectric nanogenerators and the development of biomaterials have highlighted the versatility and utility of these materials. Due to their ability to enhance triboelectric performance and the range of applications, nylons show a potential use as tribo-positive materials. Because of the easy control of their shape, they can be subsequently integrated into nanogenerators. The use of nylons has also extended into the field of biomaterials, where their biocompatibility, mechanical strength and versatility have paved the way for groundbreaking advances in medical devices as dental implants, catheters and non-absorbable surgical sutures. By means of 3D bioprinting, nylons have been used to develop scaffolds, joint implants and drug carriers with tailored properties for various biomedical applications. The present paper aims to collect evidence of these recently specific applications of nylons by reviewing the literature produced in recent decades, with a special focus on the newer technologies in the field of energy harvesting and biomedicine.